Liquid mixture of low-freezing point



Patented July 1 1, 1930 UNITED s'ra'rEs PATENT OFFICE GEOBG BEINKABT,13., O1 IUNIOH, GERMANY, ASSIGNOB, BY HESNE ASSIGNMENTS,

- Y T FUR KALTFCHEMIE G. -M. B. 8., OF MUNIGH, GERMANY LIQUID IIXT UBEOI LOW-FREEZING POINT Io Drawing. Application fled. October 8, 1888,Serial No. 810,187, and in. Germany i lovember 17, 1027.

The present invention has reference to imgrovements in heat-carriershaving a low ject is the provision of a of commercial freezing mixturesto combine but in this and other similar refrigerants an aqueoussolution of calcium chloride and an aqueous solution of magnesiumchloride,

there will be found the disadvant that owing to the hydrolithicsplitting-oil of the magnesium chloride at high temperatures anexcessive amount of muriatic acid is formed.

This disadvantage according to the present invention, is eiiectivelyprevented, by combining an aqueous solution of calcium chloride with anaqueous solution of aluminum chloride. It is true,'the aluminum chloridelikewise, splits ofi hydrolithically, but in this instance the calciumchloride suflices even at the highest obtaining temperatures assecondary lye former for complete neutralization purposes.

It is difficult to give the exact composition of the heat carrier. Thereason for this is:

Uhemically pure 0a01 dissolved in water, has a neutral reaction. It hasthe hydrogen exponent P which equals 7, that is to say, there iscontained 1 gram hydrogen in ionic form in 10' liters water.

This is determined by'means of the color indicators of SiSrensen (Opt.-rend. de Lab. Carlsberg, vol. 8, pa e 28, 1909,,orBiochemischeZeit-schrift, v0 21, pages 131, 201, of 1909) incalorimetric manner.

But practically it'is impossible. to make the heat carrier of chemicallypure 0a0l For this purpose technically pure 0a0l is used. This,dissolved in water, has an al-' kaline reaction like a lye. It dyes, forinstance, phenolphtalein red. It would, thus, leach zinc out of brassfittings.

It is said the hydrogen exponent P 0 the aqueous solution of technicallypure .09.01 is larger than 7; i. 0., there is too little H" and too muchOH; too few hyrogen ions and too many hydroxyl ions.

which,

To remedy this, there is added Al0liuntil liters water- 500 kilograms00.01,, 5 kilo r.

A101,; or for each 1,000 liters water 500' 0- grams 09.01 7 kilogr.A101,.

. In'practice, therefore, a proper solution for use may be made byadding to an aqeuous solution of 0a0l A101, until it shows a perfectlyneutral reaction; that is, when its H equals 7. h

It is well known in this art to use a pure calcium chloride solution forthe stated purposes. Such a solution has a basic reaction and has lessrust-forming tendencies than neutral solutions, but it will leach thezinc out of brassand soon cause leakage of manometers, cocks, reducingvalves and the like fittings. The new strictly neutral. solution willnot do this; besides, at equal density, it will show a higher specificheat and a lower specific viscosity than other similar solutions. Thebasic substances going into the mixture are pre-freed from the usualadmixtures in any suitable manner, and the mixture is then carefullyfiltered, and for handling and shipping purposes it may be con centratedby evaporation or reduced to solid state by centrifuging'or othersuitable means. a

What I claim 1s t A 1i uid heat carrier of low freezing point,

consisting of a mixture of an aqueous solution.

v GEORG REINHART, Jumoa.

